One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,7)(6,8)(9,10,13,17,14,18,11,15)(12,20,19,23,21,24,22,16)(25,26)(27,33)(28,31)(29,32)(30,35)(34,38)(36,40)(37,39)(1,3)(2,6)(4,7)(5,8)(9,11,14,13)(10,15,18,17)(12,19,21,22)(16,20,23,24)(25,27,28,35)(26,30,31,33)(29,34,37,36)(32,40,39,38)(1,4,5,6)(2,3,7,8)(10,15)(11,13)(16,20)(17,18)(19,22)(23,24)(26,31)(27,34)(29,37)(30,38)(33,40)(35,36)(2,7)(3,8)(9,12,14,21)(10,16,18,23)(11,19,13,22)(15,20,17,24)(27,35)(30,33)(34,36)(38,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.